1. Field of the Invention
The present invention relates to a method of manufacturing a head rest skin that covers a foamed head rest body by means of skin-integral molding. More particularly, the present invention is directed to a method of manufacturing a head rest skin adapted for pierced head rests.
2. Description of the Related Art
A pierced head rest is one type of head rest that is mounted on an upper portion of a seat back of an automobile or the like. Such head rest is usually formed into a skinned foamed product having a head resting hole in the middle thereof, and is designed so that a skin is covered over the foamed product.
This type of pierced head rest has heretofore been manufactured exclusively by covering a foamed body which has been previously prepared. As a result of this manufacturing method, a fastener is arranged around the outer circumference of the skin, and this has elevated the cost of manufacture. While different methods based on skin integrated molding employing no fastener have been proposed, it is still difficult to sew up skin forming pieces together without exposing outlet seams.
Under such circumstances, a method of sewing up skin forming pieces one by one to form an annular shape has been proposed in, e.g., Examined Japanese Patent Publication No. Hei. 4-40181.
The art disclosed in the aforementioned publication is characterized as joining together the opening edges of split cubic cylindrical segments formed of a plurality of skin forming pieces. This method has imposed a problem that the joining operation is cumbersome and time-consuming. Further, there exists also a problem that a special sewing machine such as a spot sewing machine must be employed during the process of joining one cylindrically sewn up skin forming segment to another, since the diameter of each such cylindrically sewn up skin forming segment is small.